In recent years, image processing devices for processing an endoscopic image based on imaging by an image sensor have gained in popularity (e.g., see Patent Literature 1). Meanwhile, in a case where an object with higher luminance than inside of a human body (e.g., forceps, gauze or the like) is reflected as a subject, a phenomenon may occur in which the endoscopic image is partially brightened. In particular, the endoscopic images are generally captured in a situation that the light source unit and the image sensor are close to each other, or in a situation that the light source unit and the subject are close to each other, so that such a phenomenon is likely to occur. Hereinafter, an area partially brightened by a reflection of such an object with high luminance in the endoscopic image is also simply referred to as “white area”.